AD7712 CMOS, 24-Bit Sigma-Delta, Signal Conditioning ADC with 2 Analog Input Channels

The AD7712 is a complete analog front end for low frequency measurement applications. The device has two analog input channels and accepts either low level signals directly from a transducer or high level (±4 x VREF) signals and outputs a serial digital word. It employs a sigma-delta conversion technique to realize up to 24 bits of no missing codes performance. The low level input signal is applied to a proprietary programmable gain front end based around an analog modulator. The high level analog input is attenuated before being applied to the same modulator. The modulator output is processed by an on-chip digital filter. The first notch of this digital filter can be programmed via the on-chip control register allowing adjustment of the filter cutoff and settling time.

Normally, one of the channels will be used as the main channel with the second channel used as an auxiliary input to periodically measure a second voltage. The part can be operated from a single supply (by tying the VSS pin to AGND) provided that the input signals on the low level analog input are more positive than -30 mV. By taking the VSS pin negative, the part can convert signals down to -VREF on this low level input. This low level input, as well as the reference input, features differential input capability.

The AD7712 is ideal for use in smart, microcontroller-based systems. Input channel selection, gain settings and signal polarity can be configured in software using the bidirectional serial port. The AD7712 also contains self-calibration, system calibration and background calibration options and also allows the user to read and to write the on-chip calibration registers.

CMOS construction ensures low power dissipation and a hardware programmable power-down mode reduces the standby power consumption to only 100 µW typical. The part is available in a 24-pin, 0.3 inch wide, plastic and hermetic dual-in-line package (DIP) as well as a 24-lead small outline (SOIC) package.

Features and Benefits
  • Charge Balancing ADC
    - 24 Bits No Missing Codes
    - ±0.0015% Nonlinearity
  • High Level and Low Level Analog Input Channels
  • Programmable Gain for Both Inputs
    - Gains from 1 to 128
    - Differential Input for Low Level Channel
  • Low-Pass Filter with Programmable Filter Cutoffs
  • Ability to Read/Write Calibration Coefficients
  • Bidirectional Microcontroller Serial Interface
  • Internal/External Reference Option
  • Single- or Dual-Supply Operation
  • Low Power (25 mW typ) with Power-Down Mode (100 µW typ)
Analog to Digital Converters
Data Sheets
Documentnote
AD7712: LC2MOS Signal Conditioning ADC Data Sheet (Rev. F)PDF 301 kB
Application Notes
Documentnote
AN-202: An IC Amplifier User’s Guide to Decoupling, Grounding, and Making Things Go Right for a Change (Rev. B)PDF 76.97 K
AN-389: Using Sigma-Delta Converters-Part 2PDF 590 kB
AN-388: Using Sigma-Delta Converters-Part 1PDF 590 kB
AN-311: How to Reliably Protect CMOS Circuits Against Power Supply OvervoltagingPDF 217 kB
AN-607: Selecting a Low Bandwidth (<15 kSPS) Sigma-Delta ADC (Rev. E)PDF 222 kB
AN-615: Peak-to-Peak Resolution Versus Effective Resolution (Rev. 0)PDF 70 kB
AN-397: Electrically Induced Damage to Standard Linear Integrated Circuits:PDF 149 kB
AN-283: Sigma-Delta ADCs and DACsPDF 1699 kB
AN-553: Adjusting the Calibration Coefficients on the AD771X Family of ADCsPDF 221 kB
AN-406: Using the AD771X Family of 24-Bit Sigma-Delta A/D ConvertersPDF 187 kB
Order Information
Part NumberPackagePacking QtyTemp RangePrice 100-499Price 1000+RoHS
AD7712AN Last Time Buy24 ld PDIPOTH 15-40 to 85C00N
AD7712ANZ Production24 ld PDIPOTH 15-40 to 85C22.5817.48Y
AD7712AR Last Time Buy24 ld SOIC - WideOTH 31-40 to 85C00N
AD7712AR-REEL7 Last Time Buy24 ld SOIC - WideREEL 400-40 to 85C00N
AD7712ARZ Production24 ld SOIC - WideOTH 31-40 to 85C20.5315.89Y
AD7712ARZ-REEL Production24 ld SOIC - WideREEL 1000-40 to 85C015.89Y
AD7712ARZ-REEL7 Production24 ld SOIC - WideREEL 400-40 to 85C015.89Y
Reference Materials
AD7712: LC2MOS Signal Conditioning ADC Data Sheet (Rev. F) ad7712
AN-202: An IC Amplifier User’s Guide to Decoupling, Grounding, and Making Things Go Right for a Change (Rev. B) ad7715
AN-389: Using Sigma-Delta Converters-Part 2 ad7715
AN-388: Using Sigma-Delta Converters-Part 1 ad7715
AN-397: 标准线性集成电路的电诱发损坏 (Rev. 0) ad7715
AN-615: 峰峰值分辨率与有效分辨率 (Rev. 0) ad7715
AN-607: 选择低带宽(<15kSPS)Σ-Δ型ADC (Rev. E) ad7701
AN-202: IC放大器用户指南：去耦、接地及其他一些要点 (Rev. 0) ad8021
AN-311: How to Reliably Protect CMOS Circuits Against Power Supply Overvoltaging ad1674
AN-607: Selecting a Low Bandwidth (<15 kSPS) Sigma-Delta ADC (Rev. E) ad7701
AN-615: Peak-to-Peak Resolution Versus Effective Resolution (Rev. 0) ad7715
AN-397: Electrically Induced Damage to Standard Linear Integrated Circuits: ad7715
AN-311: 如何切实有效地保护CMOS电路不受电源过压影响 (Rev. 0) adg406
AN-389: 使用Σ-Δ转换器—第二部分[中文版] (Rev. 0) ad7715
AN-388: 使用Σ-Δ转换器—第一部分[中文版] (Rev. 0) ad7715
AN-283: Σ-Δ型ADC和DAC[中文版] (Rev. 0) ad74111
AN-283: Sigma-Delta ADCs and DACs ad7715
AN-553: Adjusting the Calibration Coefficients on the AD771X Family of ADCs ad7710
AN-406: Using the AD771X Family of 24-Bit Sigma-Delta A/D Converters ad7710
MS-2210：高速ADC的电源设计 ad9861
Part 2: Circuit Suggestions Using Features and Functionality of New Sigma-Delta ad7715
Part 1: Circuit Suggestions Using Features and Functionality of New Sigma-Delta ad7715
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